Typically, a solid oxide fuel cell (SOFC) employs a solid electrolyte of ion-conductive oxide such as stabilized zirconia. The electrolyte is interposed between an anode and a cathode to form an electrolyte electrode assembly, for example, a membrane electrode assembly (MEA). The electrolyte electrode assembly is sandwiched between separators (bipolar plates). In use, normally, predetermined numbers of the electrolyte electrode assemblies and the separators are stacked together to form a fuel cell stack.
As the fuel gas supplied to the fuel cell, normally, a hydrogen gas generated from hydrocarbon based raw material by a reformer is used. In general, in the reformer, a reformed raw material gas is obtained from hydrocarbon based raw material of a fossil fuel or the like, such as methane or LNG, and thereafter, the reformed raw material gas undergoes steam reforming, partial oxidation reforming, or autothermal reforming to produce a reformed gas (fuel gas).
In this regard, a fuel cell system (fuel cell power supply apparatus) having a single unit case containing various types of components, e.g., a fuel cell, a reformer, a power converter for converting direct current power generated in the fuel cell according to a power supply output specification, a control device, and auxiliary (accessory) devices is known.
As a technique which adopts the system of this type, for example, a co-generation apparatus disclosed in Japanese Laid-Open Patent Publication No. 11-200951 (hereinafter referred to as conventional technique 1) is known. As shown in FIG. 9, a soundproof case 1 contains a gas engine 2 and a power generator 3 driven by the gas engine 2. An electrically operated coolant water pump 4 and a hot water bath (not shown) are provided adjacent to the gas engine 2. Hot water warmed by a heat exchanger (not shown) is supplied to, and stored in the hot water bath.
A waste heat radiator 5 for cooling coolant water is provided outside the soundproof case 1. A reserve tank 6 is provided above the power generator 3, and a ventilating fan 7 for air ventilation in the soundproof case 1 using electrical power generated by the power generator 3 is provided above the gas engine 2.